In Rome, Italy the cat caused a serious malfunction on a Ryanair flight, which resulted in a two-day delay.

This was reported by the media on February 9. GBnews. The incident occurred when crew members heard a meowing sound during a pre-flight check. As a result of the search, crew members found the four-legged friend in the forward electrical compartment of the Boeing 737 aircraft.
Initial attempts to capture the animal were unsuccessful, forcing the cat to flee to further compartments of the plane.
Engineers tried to get to it by removing the front panels of the cargo compartment, but these efforts were also in vain.
The animal was found when the plane door was left open - it simply went down the stairs.
After the incident, the Boeing 737 remained on the ground for two days.